package chapter08.memento;
public class MementoPattern {
	public static void main(String[] args) {
		Originator or = new Originator(); 
		Caretaker cr = new Caretaker();		
        or.setState("S0");  
        System.out.println("初始状态:"+or.getState());            
        cr.setMemento(or.createMemento()); //保存状态       
        or.setState("S1");  
        System.out.println("新的状态:"+or.getState());         
        or.restoreMemento(cr.getMemento()); //恢复状态
        System.out.println("恢复状态:"+or.getState());
	}
}
//备忘录
class Memento {  
    private String state;  
    public Memento(String state){  
        this.state = state;  
    }      
    public void setState(String state) {  
        this.state = state;  
    }
    public String getState() {  
        return state;  
    } 
}
//发起人
class Originator {  
    private String state;      
    public void setState(String state) {  
        this.state = state;  
    }
    public String getState() {  
        return state;  
    }
    public Memento createMemento(){  
        return new Memento(state);  
    }  
    public void restoreMemento(Memento m){  
        this.setState(m.getState());  
    }  
}
//管理者
class Caretaker {  
    private Memento memento;        
    public void setMemento(Memento m){  
        memento = m;  
    }
    public Memento getMemento(){  
        return memento;  
    }
}